Value of electrophysiologic testing in patients with previous myocardial infarction and nonsustained ventricular tachycardia

Previous studies of the value of electrophysiologic studies in patients with nonsustained ventricular tachycardia (VT) have been hampered by the inclusion of a small number of patients with various types of heart disease. This retrospective study was designed to assess the value of programmed stimulation in 205 asymptomatic patients who had had an acute myocardial infarction > 1 month before study. inclusion was based on 24-hour Holter monitoring during which patients had to manifest >3 consecutive ventricular beats at a rate >135 beats/min. Forty-seven (23%) patients had normal, 70 (34%) mildly impaired and 88 (43%) severely impaired left ventricular function. Programmed stimulation, using up to 3 extrastimuli, was used in each. Seventy-five patients (36%) were noninducible, 59 (29%) had nonsustained VT ( (Am J Cardiol 1990;65:594-598)
Nonsustained ventricular tachycardia (NVT) is a common cardiac dysfunction in which the ventricles, the major pumps of the heart, beat abnormally rapidly, but in a non-sustained fashion. NVT has been difficult to study, as patients at risk for NVT are not easily identified. The effects of treatment of NVT with antiarrhythmic drugs has been equivocal. The records from 205 patients found to have NVT who were studied by electrophysiology were reviewed. During electrophysiological studies, hearts were stimulated with a programmed series of electrical stimuli. Stimulation caused no arrhythmia in 36 percent of patients. NVT was found in 29 percent of patients, while sustained VT was induced in 33 percent of patients. Left ventricular dysfunction was only slightly associated with sustained VT. Of the 205 patients, 82 were left untreated, 66 were treated with medication on the basis of the electrophysiological tests, and 57 were treated with medications but not on the basis of the electrophysiological tests. The type of treatment did not alter morbidity (illness) and mortality risk from 1 to 36 months later among groups with nonsustained, sustained, or no VT, except that of three patients with sustained VT who were not treated, only one remained alive and without illness. Left ventricular function was the only important predictor of outcome. The study suggests that invasive electrophysiological testing is not predictive of further arrhythmias. The benefits of antiarrhythmic drug therapy were not apparent in this study, except possibly for sustained VT. The retrospective design (using records of past patients) limits the usefulness of conclusions, and a prospective randomized trial is needed to provide more appropriate evaluation of this condition. (Consumer Summary produced by Reliance Medical Information, Inc.)